6lo WG Agenda - IETF 104, Prague 13:50-15:50 @Karlin 1/2 Monday, March 25, 2019 Chairs: Shwetha Bhandari, Carles Gomez Responsible AD: Suresh Krishnan Minute takers: Dominique Barthel, Antoine Bernard Jabber scribe: Rahul Jadhav Meetecho for remote participants: https://www.meetecho.com/ietf104/6lo Etherpad for notes: https://etherpad.tools.ietf.org/p/notes-ietf-104-6lo?useMonospaceFont=true ---------------------------------------------------------------- AGENDA (see live meeting notes below the agenda) Introduction and draft status Bhandari/Gomez 10 min Agenda bashing; blue sheets; scribe; Jabber scribe Status of WGLC - Address Protected ND 10 min https://tools.ietf.org/html/draft-ietf-6lo-ap-nd-11 Status and Publication Request of Backbone Router Pascal Thubert 5 min https://tools.ietf.org/html/draft-ietf-6lo-backbone-router-11 ND Unicast Lookup - WG adoption 10 min https://tools.ietf.org/html/draft-thubert-6lo-unicast-lookup-00 6LoWPAN packet delivery deadline time: Last changes Charlie Perkins 15 min https://tools.ietf.org/html/draft-ietf-6lo-deadline-time-04 Update after WGLC and discussion on next steps Yong-Geun Hong 10 min https://tools.ietf.org/html/draft-ietf-6lo-use-cases-06 Update after WGLC of IPv6 Mesh over BLE networks Carles Gomez 10 min https://tools.ietf.org/html/draft-ietf-6lo-blemesh-05 Preparation for WGLC for LLN Minimal Fragment Forwarding Thomas Watteyne 10 min https://tools.ietf.org/html/draft-ietf-6lo-minimal-fragment-01 Status of Fragment Recovery Pascal Thubert 10 min https://tools.ietf.org/html/draft-ietf-6lo-fragment-recovery-02 Status of Transmission of IPv6 Packets over PLC Networks Remy Liubing 5 min https://tools.ietf.org/html/draft-ietf-6lo-plc-00 Total: 95 min ---------------------------------------------------------------- MEETING NOTES [13:51] meeting starts [13:51] intro (chairs) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-chairs-introduction-6loietf104-00 * New chairs thank Gabriel and Samita, out-going chairs, for their work * Blue sheets, Note Well. * Agenda is shown. No comments on the agenda. Chairs propose to add one item, 6lo Wiki. No objection. * Suresh: NFC doc went through IESG evaluation, lot of stuff to address there, do authors want to add details? * Y. Choi: had telechat with IESG. Would like to thank all reviewers at IESG. Will address comments and produce updated draft. * Suresh: comment that some parts looked like "marketing text", can provide help to tone it down. * Suresh (on Jabber): one of the issues was that the technology related text was very marketing-oriented. * Y. Choi: will address that New RFC (RFC 8505) since the last meeting 9 drafts updated since the last IETF Packet Delivery Deadline Time draft submitted, some reviews from various directorates, the comments were taken into account and a new draft was submitted WGLC ended on a few documents. Will be discussed today. Minimal fragment forwarding document believed to be ready for WGLC by the authors. [14:00] Status of WGLC - Address Protected ND (Pascal Thubert) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-wireless-nd-00 * Bunch called "Wireless ND" by Pascal. * Consist of series of 4 drafts that focus on ND * Multicast is not reliable because it is not acknowledged, and also often slower, uses bandwidth. * IEEE expected from the IETF that proactive neighbor discovery would be done on the (router ?) * Proposal is to register node address at Border Router. * Slide IPv6 and 802.11 : Text of the current specification for Proxy Neighbor Discovery as proposed by the IEEE * Proposing new text for 802.11 main spec, including quote to RFC8505. * The text now explains the reasons why neighbor discovery and backbone router specification are necessary * Summary on RFC8505: message sequence diagram shown. Multicast kept to a minimum (first RS from node) * The registration is done sending an NS (with EARO option) message, changes to the address registration process. * First address registration includes a TID (similar to a public key) that will prove ownership for later registration attempts. * Used to be the MAC address, a new process was proposed for security reasons * Address Protected ND has 3 crypto modes. * 6LR will challenge the joining 6LN to prove its authenticity. * This required ROVR (Registration Ownership Verifier) option field, variable length. * Shwetha : What is the opinion of the people in the room considering the WG Last Call ended on March 16 ? * Pascal: got early SecDir review. * Shwetha: no disagreemnt in the room to proceed. Will do shephard write-up. [14:16] Status and Publication Request of Backbone Router (Pascal Thubert) Layer 3 access point, proxy neighbor discovery made by the backbone router * Pascal: would be happy to get reviews. * 6BBR transforms proactive unicast registration from 6LN/6BR to DAD over the backbone. * Looking for destination results in NS lookup in broadcast. * Bridge and proxy router mode available (depending on the link between 6BBR and 6LBR) [14:20] ND Unicast Lookup - WG adoption (Pascal Thubert) * Matches a lot of proprietary implementations behavior. * Makes it standard. * We want to install 6LBR on the backbone that knows which address was registered by whom. * Created a new address mapping message, re-using the existing EDAR message type of ICMP, but defining a new code value inside the type. * lookup is now unicast as well. * Pascal goes through new message sequence diagram. Can now do unicast EDAR/ADAC to the registar on the backbone. * The big benefit of having a BBR on the backbone, you can use multicast only (but you can also fall back on the legacy system if you need it). * Pascal would like to get reviews. * Shwetha: volunteers? Rahul, Charlie. * Designed for Wi-Fi but can be useful for other networks. * Charlie Perkins: would be unusual to adopt a draft if very few people have read it * Pascal: not calling for adoption. Asking for reviews. * Carles: thanks to Rahul and Charlie. Please post your reviews on the mailing list. * Suresh: remind of the efficient-nd draft at 6man a few years back, faced opposition. Why would this one be different? * Pascal : I have been thinking about it. Pascal proposes to talk about it with Suresh the next time they meet. [14:30] 6LoWPAN packet delivery deadline time: Last changes (Charlie Perkins) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-packet-delivery-deadline-time-01 * Gone through WGLC, went to IESG, got many comments from directorates reviews. * -04 addressed these. * Assumes that devices are time synchronized. * Draft history and thanks to reviewers. * Discussion about multiple ways of representing the same time. Also, how do you know what is T0. Pretty ok for the time unit, though. * New draft addresses the T0 issue. * Suggestion by reviewer to use NTP time representation. NTP actually has 2 representations. New draft uses these, with added scaling factor to save bits. * One of the reviewers pointed out that instead of sending a complete time it would be better to send a delta encoding of the Origination Time (related to the Deadline Time), in order to save bits. * Binary point representation instead of Exponent, given the variety of representations now allowed. * Quite a lot of new additions due to addition of Synchronization to the draft. * New Format presentation. * Charlie: Will solicit new feedback for the latest version. * Pascal: forwarding based on this option should be drop or no drop. Anything else, more subtle. * Charlie: you're taking about the D bit. * Pascal: what about Quality of Service decision? * Charlie: If you want to expand, we would thank any review. * Shwetha: this draft is about deadline time. Pascal, other uses could go in separate draft. * Pascal: works. * Suresh: This hex digit is misleading, use nibbles instead. * Charlie: I was told that hex digit was better, but no problem to use nibbles. [14:45] Update after WGLC and discussion on next steps (Yong-Geun Hong) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-draft-ietf-6lo-use-cases-06-00 * Co-authors are each experts in different 6lo technologies. * This document is 2 1/2 years old. Purpose is to help newcomers understand how to use 6lo over various technologies. * May not be interesting to 6lo experts but has some real potential for future adopters. * WGLC was done in late 2018, but no comment was received. Maybe because it is very good! * Updated anyway to include PLC, and reflect advances in various documents referenced by this one. * 4 6lo scenarios. * HomePlug Alliance has stopped operating, rumored to transfer its standardization activity to Wi-SUN, but no official announcement. * Shwetha: living document. Should be published as an Informational document, or keep it in the 6lo Wiki? * Yong-Geun: what is the 6lo Wiki? * Carles: Place where different resources about the working group can be found: https://trac.ietf.org/trac/6lo * YGH: could be. Would still like to uprade doc with expert comments. * Pascal: What do we expect from 6lo in the future, would be cool to keep the document open. * Carles (as a co-author): would like to know how to interpret the silence during WGLC. * Shwetha: what does Suresh think? * Suresh: Not sure about the archival value of the draft, and also about the scope of the draft. If we decide to go for publication we will probably need to chop down a bit of it. * YGH: point taken. Will discuss with co-authors. Will considering narrowing down the scope. [14:52] Update after WGLC of IPv6 Mesh over BLE networks (Carles Gomez) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-ipv6-mesh-over-ble-00 * WGLC on -04, comments received, -05 released addressing those comments. * Therefore authors believe doc is ready for next step. * Going through list of updates: - Terminology consistency - Not sure if doc is sufficient by itself to build a mesh over BTLE. Now made clear that it is not enough, e.g. does not define routing. - Fragmentation was not explicitly addressed, it is now with BTLE4.2 uses L2CAP fragmentation - Now refers to RFC8505 regarding ND. Discusses use of crypto addresses, protected ND... - Updated the security consideration part in the draft or by referencing other drafts (such as 6lo-ap-nd) * Questions? * Shwetha: does it address all reviewers’ comments? Nodding in the room. [14:59] Preparation for WGLC for LLN Minimal Fragment Forwarding (Thomas Watteyne) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-minimal-fragment-forwarding-00 * Thomas reviews RFC4944 fragmentation, explains why per-hop F/R is problematic: - Latency - Memory constraint * Proposition to use fragment forwarding, will send the data without reassembling until the destination. * To describe that solution, 2 drafts at 6lo WG (minimal FF, frag recovery), 1 at lwig WG (virtual reassembly). * Minimal FF draft posted recently as an Informational draft to present the problem and the solution that is to be adopted. * Shows simulation results (simulation by Yatch on 6TiSCH simulator), which highlight the problem and the effectiveness of the solution. - the solution proposed reduces the memory usage and prevents packet loss * Believe draft is stable, asking about WGLC? * Carles: comments on this document? None heard. * Carles: will open WGLC, volunteers? George, Dominique [15:07] Status of Fragment Recovery (Pascal Thubert) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-fragment-recovery-00 * Thanks to Thomas for the introduction, will present the complementary work of the previous presentation. * Minimal FF does not address classical case of one lost fragment. Reassembly buffer blocked. * This draft about recovering the missing fragment(s). Similar to SCHC fragmentation. * You send the fragment, you receive an Ack bitmap that indicates which fragments were lost. * Cannot use RFC4944 format, defined new one. * With Flow Control, ECN, etc. * Implementations provided comments. Format did not allow for very large frames. * Format modification to reduce the size of the datagram tags, bits saved for datagram size field, therefore allows for large datagrams. (15.4g has 2 KiB frames.) * 6LoWPAN compression might change size of packet, had to include slack to allow for change in size on retransmission depending on the capacities of the devices that handle the packet. * Need to change the way a packet is handled without changing it depending on if you are the sender, the receiver or an intermediary. * Pascal: implementers are happy. Ready for WGLC? * Laurent: why not use SCHC meachanism instead? * Pascal: because this existed before SCHC. * Pascal: Would love to have reviews from the SCHC authors. One difference is that SCHC does not handle multiple hop retransmission. * Carles and Laurent to review before asking for WGLC. [15:15] Status of Transmission of IPv6 Packets over PLC Networks (Remy Liubing) https://datatracker.ietf.org/meeting/104/materials/slides-104-6lo-status-of-transmission-of-ipv6-packets-over-plc-networks-00 * Reviews history of this draft. Originally written by Huawei. * PLC used for more applications than metering. To control traffic lights, etc. * New uses now need Layer 3. * G.9903, P1901.1 and P1902 are in scope of ths draft. * Was adopted and re-submitted as WG draft. * Not received a lot of comments, only 1 by Carsten, relating to confusing PLC landscape description. Description includes wide range of PLC technologies. * Added some clarification following this comment, that this draft focuses on constrained PLC. * Future work will add more references to header compression RFCs. * Feedback is requested. * Carles: are you aware of any implementations? * Remy: Some implementation exist. * Carles: It would be good to use these implementations as a work base to improve the specification. [15:21] 6lo Wiki (Carles as chair) * Requests that useful information is provided to populate the wiki. * Useful information includes open source implementations, interop events, etc. [15:22] Any other business? [15:22] Meeting adjourns.